Motor fuel composition



3,054,666 Patented Sept. 18, 1962 3,054,666 MOTOR FUEL COMPOSITION Richard F. Neblett, Plainfield, and William E. Lovett,

Westfield, N.J., assignors to Esso Research and Engineering Company, a corporation of Delaware No Drawing. Filed Mar. 17, 1960, Ser. No. 15,527 22 Claims. (Cl. 44-58) The present invention relates to improved motor fuel compositions, and more particularly, to an improved motor fuel composition comprising additive agents adapted to reduce or prevent engine manifold deposits.

The use of solvent oils in gasoline compositions to lubricate the moving parts in the upper section of the engine has long been known. Solvent oils in gasoline are generally utilized in amounts from about 0.25% to about 0.75% by volume to prevent valve stem and piston ring sticking, and to serve as a general purpose upper cylinder lubricant. The solvent oils generally employed are hydrocarbonaceous materials having selective solvent action for hydrocarbon gums, sludges, and varnish engine deposits. However, oxygenated gums and resins are not readily removed by these solvent oils, and it would be highly desirable to employ as a solvent oil or as an adjuvant to solvent oils a composition that has high specificity for gums and varnishes. In the past, various oxygenated solvents have been added to gasoline for this purpose, but these materials have not been wholly efiective, either because of too high vapor pressure at motor operating conditions, or because excessive quantities were required. Thus, it has been suggested that high boiling esters such as amyl stearate be employed as a solvent oil. This composition, however, has not given satisfaction and its solvent powers are inadequate.

The need for a highly active solvent oil type additive has been long recognized. Manifold deposit and intake port deposit buildup represents a series fueldeficiency, particularly when the fuel is used in low temperature service with considerable engine idling time. Catalytically cracked gasolines which have comparatively high octane numbers, and are thus widely used, are unstable and require the use of an antioxidant. Both these unstable fuels and antioxidant residues contribute to manifold deposits. Use of a solvent oil type additive represents a desirable method of minimizing these deposits.

It has now been found that excellent solvent oils may be prepared by the acylation of particular liquid synthesis Oxo bottom products derived from the reaction between olefins, carbon monoxide and hydrogen in the presence of a metallic carbonylation catalyst. These acylated Oxo bottom products have been discovered to be excellent solvent oils either alone or in combination with conventional type solvent oil.

It is therefore an object of this invention to provide improved motor fuel compositions containing a new and superior solvent oil. More particularly, it is an object of this invention to set forth an improved motor fuel composition containing a superior solvent which reduces or prevents excessive octane quality degradation of the gasoline in which it is employed while reducing the formation of intake valve underside deposits, intake manifold deposits, and the like. Further objects of this invention, as Well as nature and scope of this invention, will become more apparent from the subsequent description.

The carbonylation, or Oxo reaction, as it is commonly called is well known in the art as a method of preparing alcohols from olefins, the former having one more carbon atom than the olefin from which it is derived. It is a twostage synthesis wherein, in the first stage, olefin, CO, H and a cobalt catalyst are reacted at pressures of about 20004000 p.s.i.g. and temperatures of 275 to 375 F. to form an aldehyde product containing one more carbon atom than the parent olefin, and the aldehyde product is subsequently hydrogenated to form the corresponding alcohol. The process is described in U.S. Patent 2,327,066 to Roelen; 2,504,682 to Harlan and in many subsequent patents. It is the still pot residues after the distillation of the alcohol fraction, commonly referred to as Oxo bottoms that are the acylated components of the present invention. In the carbonylation of a heptene fraction obtained from propylene-butylene copolymerization, for example, the bottoms represent about 15-30% of the crude alcohol charged to the distillation zone. The Oxo bottoms are believed to consist primarily of highly branch chained ether-alcohols, alcohols, acetals, ethers, both saturated and unsaturated, and minor amounts of other oxygenated compounds, such as aldols, esters and the like. Recent studies have indicated that the principal components of Oxo bottoms are ether-alcohols with saturated and unsaturated ethers present in lesser amounts. The Oxo bottoms derived from the oxonation of a C olefin are believed to be substantially composed of C ether-alcohols. A typical inspection of the Oxo bottom composition obtained from carbonylation of a heptene polymer fraction was as follows:

Hydroxyl No. 215

Free carbonyl No 1.9 Combined carbonyl No 29 Saponification No. 21 Gravity, API 33.3 Acid No. 0.2

Though for any paritcular olefin fraction being carbonylated the magnitude of these constituents may vary, the relative proportions generally remain fairly constant. Thus, a propylene fraction, a heptane fraction, a C and a C fraction may be carbonylated and the bottoms employed. The constituents of Oxo bottoms are all characterized by being highly branch chained, even though relatively straight chain olefins are originally carbonylated. This arises out of the isomerizing characteristics of the cobalt carbonyl catalyst, and the fact that the addition of the H CO group may be to any of the double bonds.

7 A sample of a C Oxo bottoms has the following Engler distillation at 10 mm.

The superior solvent 'oils of the present invention are prepared by the acylation of the above-described Oxo bottoms. Preferred superior solvent oils can be' prepared by the acetylation of the above-described Oxo bottoms. Acylation and acetylation can be accomplished by methods well known to those skilled in the art, such as by the direct reaction of the Oxo bottomswith suitable acylating or acetylating agents. The reaction may, if desirable, although it is not required, be carried out in the presence of a suitable diluent such as benzene, hexane, acetone, and the like. Thev preparation of these acylated and acetylated Oxo-bottoms can be aided by the utilization of suitable catalytic agents well known in the art, such as pyridine, boron fluoride etherate, sodium acetate, dilute sulfuric acid, aluminum chloride, and the like.

Suitable acylating agents for use in preparing the solyent oils of this invention include substituted and unsubstituted, saturated and unsaturated, aliphatic, aromatic and aliphatic-aromatic carboxylic acids having from 1 to 30 carbon atoms per molecule and their acid halide and anhydride derivatives. Preferred acylating agents are those saturated unsubstituted acids, acid halid derivatives, and anhydrides of benzoic and aliphatic acids and combinations thereof having from 1 to 12 carbon atoms per molecule. Specific examples of suitable acylating agents include benzoic acid, benzoyl chloride, acetic anhydride, phthalic anhydride, acetoacetic acid, ethyl chlorocarbonate, trimethylacetic acid, phenyl acetic acid, propionyl chloride, acetic propionic anhydride, capryl chloride, and the like. Specific examples of suitable acetylating agents include acetic acid, acetyl chloride, ketene, and the like.

The amount of acylating agent to be utilized in the preparation of the solvent oils of the invention will in partbe dependent upon the general composition of the OX bottoms employed and the chemical nature of the acylating and acetylating agents. In general, the reactants should be utilized within the range of 0.1 to 1.5 moles of acylating agent for each mol of hydroxyl in the OX0 bottoms with a range of 0.8 to 1.2 moles preferred. The invention is in general carried out within a temperature range of 20 F. to 40 F. with the temperature not being critical. The time for the reaction varies, is not critical, and depends in general on such factors as the quantities involved, temperature, acylating agent and composition of 0x0 bot-toms utilized and the like. The motor fuels and more particularly the gasolines in which the acylated Oxo bottoms of the present invention may be utilized are conventional gasolines for use in internal combustion engines. Such gasolines are supplied in a variety of grades, depending upon the particular service or use for which they are intended. The most general classifications applied to such fuels are those of motor gasolines and aviation gasolines. Motor gasolines are defined by ASTM Specification D-43956T and are designated as type A, type B, or type C, depending upon the particular service for which they are to be used. Such fuels consist of mixtures of hydrocarbons of various types, including aromatics, olefins, paraffins, isoparatfins, naph thenes, and in some cases diolefins derived from petroleum by refining processes such as fractional distillation, thermal cracking, catalytic cracking, hydroforming, alkylation, isomerization and solvent extraction. Motor gasolines normally boil between about 80 F. and about 450 F. when tested by ASTM Method D-86. Their vapor pressures as determined by ASTM Method D323 vary,"d'epending on the season of the year during which they are to be used, from about 7 to about 15 psi. at 100'F. Their octane numbers, as determined by ASTM Method D-908, may range from about 83 to about 105 or higher. Aviation gasolines are prepared by blending of constituents similar to those found in motor 'gasolines but, in general, have somewhat narrower boiling ranges between 100 F. and 330 F., and somewhat more rigid specifications than do motor gasolines. Specifications for aviation gasolines are set forth in US. Military Specification MILF5572. The Reid vapor pressure of aviation gasoline is 7 p.s.i. For use under special conditions, aviation gasoline may have lower vapor pressure than provided in these specifications, if its overall volatility is suitable. V Y

The acylated OX0 bottoms of the instant invention may be usefully employed either-aloneror incombination with conventional solvent oils having an SUS viscosity of from about 50 to about 500 seconds at 100 F. Gasoline compositions improved by the addition of the acylated OX0 t bottoms of the invention may contain other additives conventionally employed in gasolines such as metallic organo antiknock agents, phosphorus and halogenated scavenging agents, upper cylinder lubricating oils, corrosion inhibitors, gum inhibitors, anti-icing additives, dyes, sludge dispersants, detergents'and the like.

In carrying out the invention a small amount sulficient to be effective as a solvent oil of the acylated OX0 bottoms is either added alone or in combination with a conventional solvent oil to the gasoline itself, or is injected into the manifold in any desired manner in order to contact the gum and resin coated surface. The amount of acylated OX0 bottoms to be utilized may vary over a wide range depending upon various factors such as the type of motor fuel being used and the type of engine. In general, from 0.5% to about 5.0% by volume of the acylated OX0 bottoms is sufiicient, and preferably the amount used is between 0.25% and 2.0% by volume based on the gasoline blend. The acylated OX0 bottom solvent oils of the invention can be effectively combined with from 90 to by volume of conventional solvent oil, and preferably between and 60% by volume of commercial solvent oil is employed.

The exact motive and objects of the invention can best be understood by reference to the following examples.

EXAMPLE 1 The acetylated Oxo bottoms of the present invention were prepared as follows:

Two hundred sixty-one (261) grams of OX0 bottoms derived from the production of C OX0 alcohol were placed in a cylinder and reacted with forty-two (42) grams of ketene derived from the thermal decomposition of acetone vapor. The reaction was accomplished by passing the ketene gas into the cylinder. The reaction was continued until there was no further increase in the temperature of the water bath surrounding the reaction vessel. Three hundred twenty-five (325) (107% of theoretical) grams of acetylated OX0 bottoms product were recovered. Inspection of the 0X0 bottom sample prior to acetylation indicated a composition comprising about 96 wt. percent of C ether-alcohol and about 4 Wt. percent of C alcohol. The inspections of the 0x0 bottoms before and after acetylation with ketene are as follows:

Table I The Oxo bottoms and the acetylated OXo bottoms of Example 1 were incorporated into a base gasoline having the following characteristics.

ASTM distillation Initial boiling point F 95 10% boiling point F 143 50% boiling point F 227 boiling point F 281 Final boiling point 328 Gravity, API 59.2 Reid vapor pressure, p.s.i 8.25 Research Octane No. 105.0 Motor Octane No. 94.5

This base gasoline was a high quality premium gasoline containing 3 cc./ gallon of tetraethyl lead antiknock additive with 1.0 theory ethylene dichloride and 0.5 theory ethylene dibromide.

Laboratory octane ratings of the Research Octane Number and the Motor Octane Number were obtained with the fuel compositions by using the Direct Match Method. The Direct Match Method of determining octane rating numbers is based upon the determination of the octane rating of the test sample side by side with a calibrated prototype sample of similar antiknock quality and composition in the same engine and at the same compression ratio while feeding the samples alternately through separate carburetor bowls in parallel. The differences between the calibration octane values and the determined octane rating for the prototype fuel are added algebraically to the octane rating of the test sample to obtain corrected octane ratings for the said test sample. The apparatus and procedure used in this Direct Match Method is the same apparatus and general procedure to determine octane ratings by ASTM Method D-908 and ASTM Method D357. The calculations and reporting are done by subtracting the prototype rating from its calibration value and adding this AO.N. algebraically to the rating of the test sample to obtain a corrected rating for the test sample. The corrected octane rating is then reported.

The Research Octane Number (RON) of both base gasolines was determined by the Standard ASTM Research Method Test Procedure D908-51, which is de scribed in the 1952 edition of ASTM Manual of Engine Test Methods for Rating Fuels. The Motor Octane Number (MON) of both base gasolines was determined by the Standard ASTM Motor Method Test Procedure D357, which is set forth in the 1953 edition of ASTM Manual of Engine Test Methods for Rating Fuels.

Laboratory octane rating changes of the base gasoline test compositions with varying amounts of OX bottoms and acetylated OX0 bottoms were determined by the Direct Match Method with the following results:

Table II CHANGE IN THE OCTANE NUMBER 1 (AO.N.)

AResearch AMotor Vol. Percent of Add.

111 Base Gasoline Acetylated Bottoms 0x0 Bottoms Acetylated 0x0 Btms.

1 Average of duplicate determinations.

EXAMPLE 3 The superior ability of the acylated Oxo bottoms to to reduce or prevent the formation of intake manifold deposits was determined by tests run in a Lauson engine whereby the gasoline used had ketene acetylated Oxo bottoms as an additive solvent oil.

After the engine test of approximately hours duration the manifold was washed first with heptane and then with acetone. The solvents were then evaporated from the washings and the weight of the deposits determined. The amount of heptane insoluble, acetone soluble deposits are indicative of the ability of the solvent oil to prevent or reduce manifold deposits.

N 0 Additivc Acetyl- B ottoms ated OX0 Bottoms Acetone soluble deposits, mgsJlb. fuel--- 4. 8 3. 0 0. 9

The above data demonstrates the remarkable effectiveness of acylated Oxo bottoms as a solvent oil in reducing engine manifold deposits. The unexpected superiority of acetylated Oxo bottoms over the use of 0x0 bottoms as solvent oil is readily apparent from this data.

EXAMPLE 4 Preferred Acceptable Viscosity SUS sec. at 100 F Pour point, F -max In general, acylated Oxo bottoms may be incorporated alone or with any commercial solvent oil into fuels such as gasoline, diesel fuels, jet fuels, and the like.

What is claimed is:

l. A motor fuel composition comprising a major amount of hydrocarbons boiling in the gasoline range and a small amount suflicient to reduce engine manifold deposits of acylated Oxo still bottoms obtained byreact ing hydrogen, carbon monoxide and an olefin having from 2 to 15 carbon atoms at elevated temperatures and pressure in the presence of a carbonylation catalyst to produce an aldehyde product, hydrogenating the aldehyde product to an alcohol, removing the major portion of the C to C alcohol component by distillation leaving behind Oxo still bottoms, and thereafter acylating the said OX0 still bottoms with a carboxylic acylating agent selected from the group consisting of aliphatic, aromatic and aromatic-aliphatic carboxylic acids and their acid halides and anhydrides having from 1 to about 30 carbon atoms per molecule, the ratio of moles of acylating agent to each mole of hydroxyl in the 0x0 bottoms being between 0.1 and about 1.5.

2. The motor fuel composition as defined by claim 1 wherein said small amount of said acylated Oxo still bottoms is about 0.05 to about 5.0% by volume of the fuel composition.

3. The motor fuel composition as defined by claim 1 wherein the said mol ratio of acylating agent to hydroxyl is between 0.8 and 1.2.

4. The motor fuel composition as defined by claim 1 wherein said acylating agent is ketene.

5. The motor fuel composition as defined by claim 1 wherein said acylating agent is acetic anhydride.

6. The motor fuel composition as defined by claim 1 wherein said composition contains additionally a small amount of a solvent oil having a viscosity of about 50 to about 500 Saybolt Universal seconds at 100 F., said small amount being between and 50% by volume of the total solvent oil and acylated 0x0 bottom volume.

7. The motor fuel composition as defined by claim 1 wherein said olefin has from 6 to 8 carbon atoms.

8. The motor fuel composition as defined in claim 1 wherein the said acylating agent is selected from the group consisting of unsubstituted saturated aliphatic and benzoic carboxylic acids and their acid halides and anhydrides having from 1 to about 12 carbon atoms per molecule.

9. A leaded gasoline fuel composition for use in internal combustion engines comprising a major amount of hydrocarbons boiling in the gasoline range and from 0.05 to about 5.0% by volume of acylated Oxo still hottoms obtained by reacting H CO, and an olefin having from 6 to 8 carbon atoms at elevated temperatures and pressures in the presence of a carbonylation catalyst to produce an aldehyde product, hydrogenating the aldehyde product to the alcohol, removing the major portion of the C to C alcohol component by distillation, leaving behind OX still bottoms product, and thereafter acylating the said OX0 still bottoms using a carboxylic acylating agent selected from the group consisting of aliphatic, aromatic, and aliphatic-aromatic carboXylic acids and their acid halides and anhydrides having from 1 to about 12 carbon atoms per molecule, the ratio of moles of acylating agent to each mole of hydroxyl in the OXo bottom being between 0.8 and about 1.2.

10. The leaded gasoline fuel composition as defined by claim 9 wherein said composition contains additionally from 0.25% to about 0.75% by volume of a hydrocarbon solvent oil having a viscosity at 100 F. of about 50 to about 500 Saybolt Universal seconds.

11. The leaded gasoline fuel composition as defined by claim 9 wherein said amount of acylated OX0 still bottoms is from 0.25% to about 2.0% by volume of said fuel composition.

12. The leaded gasoline fuel composition as defined by claim 9 wherein said OX0 still bottoms are derived from the oxonation of a butylene-propylene copolymer.

13. The leaded gasoline fuel composition as defined by claim 9 wherein said acylating agent is ketene.

14. The leaded gasoline fuel composition as defined by claim 9 wherein said acylating agent is acetic anhydride.

15. The leaded gasoline fuel composition as defined by claim 9 wherein said fuel contains additionally about 3 cc./ gal. of tetraethyl lead.

16. An improved solvent oil composition having an enhanced ability to reduce engine manifold deposits, said solvent oil being obtained by reacting hydrogen, carbon monoxide and an olefin having from 2 to 15 carbon atoms at elevated temperatures and pressure in the presence of a carbonylation catalyst to produce an aldehyde product, hydrogenating the aldehyde product to an alcohol, removing the major portion of the C to C alcohol component by distillation leaving behind OX0 still bottoms, and thereafter acylating the said OX0 still hottoms with a carboxylic acylating agent selected from the group consisting of aliphatic, aromatic and aromatic-aliphatic carboxylic acids and their acid halides and anhydrides having from 1 to about 30 carbon atoms per molecule, the ratio of moles of acylating agent to each mole of hydroXyl in the OX0 bottoms being between 0.1 and about 1.5.

17. The solvent oil composition as defined by claim 8 16 wherein said composition contains additionally between to 90% by volume of a hydrocarbon solvent oil having a viscosity of about 50 to 500 Saybolt Universal seconds at 100 F.

18. The solvent oil composition as defined by claim 16 wherein said acylating agent is ketene.

19. The solvent oil composition as defined by claim 16 wherein said olefin has from 6 to 8 carbon atoms.

20. The solvent oil composition as defined by claim 16 wherein said acylating agent is acetic anhydride.

21. The solvent oil composition as defined by claim 16 wherein the said acylating agent is selected from the group consisting of unsubstituted saturated aliphatic and benzoic carboxylic acids and their acid halides and anhydrides having from 1 to about 12 carbon atoms per molecule.

22. An improved solvent oil composition having an enhanced ability to reduce engine manifold deposits, which solvent oil comprises from 50 to 90% by volume of a hydrocarbon mineral oil having a viscosity at 100 F. of between and Saybold Universal Seconds and fiom 10 to 50 vol. percent of acylated OX0 still bottoms obtained by reacting hydrogen, carbon monoxide, and an olefin having from 6 to 8 carbon atoms at elevated temperatures and pressures in the presence of a carbonylation catalyst to produce an aldehyde product; hydrogenating the aldehyde product to the alcohol; removing the major portion of the C to C 5 alcohol component by distillation, leaving behind OX0 still bottoms product; and thereafter acetylating the said OX0 still bottoms with ketene in the ratio of between 0.8 and 1.2 mols of ketene to each mol of hydroXyl in the OX0 bottoms, said acetylated OX0 bottoms having a carbonyl number of approximately 79.2 and a hydroXyl number of approximately 58.5.

References Cited in the file of this patent UNITED STATES PATENTS 2,236,590 Backofi et al. Apr. 1, 1941 2,284,080 Backofi et al. May 26, 1942 "2,646,348 Neudeck July 21, 1953 2,789,891 Brandes et al. Apr. 23, 1957 2,802,024 Fasce et al. Aug. 6, 1957 2,843,463 Gaston et al. July 15, 1958 2,922,706 Durr et al. Jan. 26, 1960 2,936,315 Whitaker May 10, 1960 2,955,122 Whitaker Oct. 4, 1960 

1. A MOTOR FUEL COMPOSITION COMPRISING A MAJOR AMOUNT OF HYDRCARBONS BOILING IN THE GASOLINE RANGE AND A SMALL AMOUNT SUFFICIENT TO REDUCE ENGINE MANIFOLD DEPOSITS OF ACYLATED OXO STILL BOTTOMS OBTAINED BY REACTING HYDROGEN, CARBON MONOXIDE AND AN OLEFIN HAVING FROM 2 TO 15 CARBON ATOMS AT ELEVATED TEMPERATURES AND PRESSURE IN THE PRESENCE OF A CARBONYLATION CATALYST TO PRODUCE AN ALDEHYDE PRODUCT, HYDROGENATING THE ALDEHYDE PRODUCT TO AN ALCOHOL, REMOVING THE MAJOR PORTION OF THE C3 TO C16 ALCOHOL COMPONENT BY DISTILLATION LEAVING BEHIND OXO STILL BOTTOMS, AND THEREAFTER ACYLATING THE SAID OXO STILL BOTTOMS WITH A CARBOXYLIC ACYLATING AGENT SELECTED FROM THE GROUP CONSISTING OF ALIPHATIC, ARONATIC AND AROMATIC-ALPIHATIC CARBOXYLIC ACIDS AND THEIR ACID HALOIDES AND ANHYDRIDES HAVING FROM 1 TO ABOUT 30 CARBON ATOMS PER MOLECULE, THE RATIO OF MOLES OF ACYLATING AGENT TO EACH MOLE OF HYDYROXYL IN THE OXO BOTTOMS BEING BETWEEN 0.1 AND ABOUT 1.5. 